Q86 / 180 · NEET 2026 (Cancelled) · Chemistry
The functional group that can be identified through phthalein dye test is :
- AAldehyde
- Correct answerBPhenolic
- CCarboxylic acid
- DAlcohol
Solution
The phthalein dye test is a characteristic test used for the identification of the phenolic functional group.
When a phenol is heated with phthalic anhydride in the presence of concentrated sulfuric acid, it undergoes a condensation reaction to form a colorless compound, phenolphthalein.
Upon adding an alkaline solution like dilute sodium hydroxide (NaOH) to this mixture, a characteristic pink or red color is produced due to the formation of the phenolphthalein anion.
Therefore, the functional group identified through the phthalein dye test is phenolic.
Answer: Phenolic
When a phenol is heated with phthalic anhydride in the presence of concentrated sulfuric acid, it undergoes a condensation reaction to form a colorless compound, phenolphthalein.
Upon adding an alkaline solution like dilute sodium hydroxide (NaOH) to this mixture, a characteristic pink or red color is produced due to the formation of the phenolphthalein anion.
Therefore, the functional group identified through the phthalein dye test is phenolic.
Answer: Phenolic
Hence, the correct answer is option: 'B'.